Star Tech Journal

Issue: 1988-June - Vol 10 Issue 4

(
STAR*TECH Journal
)
June 1988
6
Bally Midway 7533 DAC Failures
Arnie Aarstad
Bally Midway Service Dept.
Franklin Park, Illinois
SUBJECT
Premature failure of the 7533 DAC's on the
sound boards. During extensive research on
the sound board's Digital to Analog con-
verter circuit, we have discovered a transient
condition which may result in premature
failure of this part.
CAUSE
This condition is due to overstressed metali-
zation related to pin 1 on this chip. The
situation occurs on power-down when the
Vee begins to fall and reaches about 1.5
volts. At this time, the voltage on pin 1
exceeds Vee for a fraction of a second. The
DAC is not designed to withstand this con-
dition.
CURE
Remove the 4 7uF capacitor connected to pin
1 of this chip. This will eliminate the tran-
sient condition on the circuit, and testing
indicates that this removal has no negative
effect on the overall operation of the circuit.
To remove the correct capacitor use the following guide .
• · ·•.· •.• •. Board Series
Item
• i\084-91863
A084-91671
• A084-91671
A084-91779
A084-91855
A084-91864
1.
2.
3.
4.
5.
6.
Board Name
Remove Capacitor
Sounds Good (Video)
Cheap Squeak Deluxe (Video)
• Artificial Artist (Video)
Turbo Cheap Squeak (Video)
T.C.S. Pinball (Pinball)
Sounds Deluxe (Pinball)
Cl22
Cl22
Cl22
Cl2
C30
Cl2
The following games use one or more of the sound boards identified by their item numbers:
Pinballs
Black Belt (5.)
City Slicker (5.)
Dungeons & Dragons (6.)
Escape from the Lost World (6.)
Hardbody (5.)
Heavy Metal (6.)
Motordome (5.)
Party Animal (6.)
Special Force (6.)
Strange Science (5.)
Videos
Demo Derby (4.)
Max R.P.M. (4.)
Power Drive ( 1.)
Rampage (1.)
Sarge (4.)
Spy Hunter (2.)
Spy Hunter II (l.& 4.)
Star Guards (1.)
Xenophobe (1.)
Zwackery (3.)
• Merit Pub Darts Static ProbleIIl & Updates
Jim Kelly, Customer Service Mgr.
Merit Industries
Bensalem, Pennsylvania
Segment" or "Stuck Button" on power up.
A new four player Cricket game called "Cut
Throat Cricket" has been added in this pro-
gram change.
PROBLEM
The first production run of Pub Time Premier
Darts may be subject to static problems. The
game could lock up, refuse to accept credits
or put up excessive credits due to static
shock.
INSTALLATION
This new program (2278-00 U3-1A, U20-1A
and U2 l -1A) is installed by changing 3
Eproms on the DRT'-950 Pcb. This update is
available by calling your Merit distributor.
SOLUTION
An Anti-Static Kit is now available, at no
charge, through Merit Industries or your
local Merit distributor.
NOTE
When this program is installed, a Ram Clear
must be performed by using switches 1 and
2 of Dipswitch 2. If there are any questions
about the Anti-Static Kit, the Program Up-
date or any Merit product, please call Cus-
tomer Service at 1-800 / 445-9353.
PROGRAM UPDATE
/A This program change enlarges the players
'911' score numbers on the video monitor. In
addition, the game will now display a "Stuck
52'6'~
Great Quality at a Great Price
MARKER TIES
NYLON CABLE TIES
Length
Stock
3 112"
5 112··
7 112··
9½"
SCl00
SC1405
SC190
SC250
#
Price per 100
2.00
3.00
5.20
8.00
Price per 1000
10.00
15.00
26.00
40.00
Length
Stock
#
4
112"
SCll0
CABLE CLAMPS
sew
Size
sc0
Stock#
SC-1
SC-2
SC-3
SC-6
SC~
Price per 100
6.00
7.00
8.00
12.00
.._
1"
Price
Price
per 100
per 1000
7.00
35.00
Size
l
3/ 16"
Stock
Price
Price
#
per 100
per 1000
20.00
160.00
SC-30
Ordering Information
Call Toll Free 1-800-537-2327 (Randy or Tania)
or Write 50th State Coin-Op 91-246 Oihana Street,
Ewa Beach, Hawaii 96707
Fax 808-682-4016 Telex 7430602FUNCO
VISA & Master Card Accepted
SC©
Price per 1000
30.00
35.00
40.00
60.00
__________________ _
1; 4"
3; 8''
1/ 2''
BUTTON PLUG
Volume Discounts on
25,000 pieces per Stock No.
Large Quantity Always In Stock

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